Adjust No2 Secondary Throttle Valve?
 

Trying to adjust my idle. Believe that the No2 Secondary throttle valve is open too far. There's a U shaped tab that stops against a post/boss that prevents the valve from closing any further when I try to manually close the valve with my finger. Do I need to bend that U shaped tab?

The FSM isn't real clear on the No2 Secondary valve adjustments. Says that they should be closed when applying pressure to the double throttle diaphram. They definitely aren't closed.

Any suggestions?

Pics attached.

Here's the tab that stops against the post.

Here's the post from the front.

Hey NZ or Hailers...you guys out there?

Been reading your threads on throttle valves and need your help on this. Do these No2 Secondaries look too far open? Do I pinch those tabs together to increase the stoke on the dashpot to further close the valves?

Thanks...hope you guys find me.

those valves that you are pointing to in your picture are not the secondary throttle plates...those are like a choke or something...like on a carb. they won't affect your idle. the secondary throttle plates are behind those. look further down your throttle body. you can remove that whole choke assembly and it will allow more air into your engine....just remember to put JB-weld over the left over holes. does that help?

You should not be touching the secondary throttles to adjust idle. They have nothing to do with it.

Agreed. That set will not effect the idle at all. Its the No.1 secondary throttle plates the might cause a problem if they were open a touch. The No.1 secondary throttle plates should not open until the primary throttle plate has already opened approx 0.04 to 0.07.

So take a look at the No.1 secondary throttle plate and see if its fully closed when the primary throttle plate is closed

Sad to say I can't tell you how to set the No.2 throttle plates since I've never really had a black cam with its dashpot to ocntrol the things. Mine just spring to full open.

If your having a really fast idle and your trying to control it......take a look at the rear of the throttle body and examine the thermowax. Maybe pour boiling water over the thermowax to see it the thermowax piston will extend and if the fast idle cam comes off the roll pin.

Thanks for the replys guys.

Just for clarification, I'm holding these No2 Secondaries down with my finger to see how far they close. Normally they're sprung open horizontal. See the attached pic.

I thought that when the car was cold these No2 secondaries are supposed to close....in my case they wouldn't close all the way, letting air past, potentially causing more fuel to get dumped in. If that's not the case, I'm barking up the wrong tree.

Let me give you the problem I'm trying to solve.
3K rpm idle is fine (17 sec)

After the high rpm idle above is completed, I have my problem. The rpms increase and drop between a 300rpm range (1200 to 1500) at a frequency about every 2 sec. It does this for a while until the car warms up. If the

Then it settles in nicely to a lower rpm ( I think around 800).

From the picture, I just attached, it sure looks like the No1 Secondaries are completely closed when my primary throttle valve is completely closed.

I measured the gap from the bore to the throttle valves (No1 secondary and primary) with a pc of 12 mil wire.
- I can just barely slip the wire past the primary valve at the bottom of the bore. As I move 1/8 inch away (left or right) I can't get the wire past.

- I can't get the 12 mil wire past the No1 secondaries anywhere.

I think these are all set per the FSM spec.

If the thermowax piston is supposed to expand when the engine is hot, thereby opening the primary/No1 secondary valves, then isn't that a warm idle function? Would I need to consider the thermowax piston position based on trying to resolve my cold idle problem?

What next? Really appreciate your help guys! Thanks for spending the time to help me.

PARTIAL ANSWER due to time constraints: You are barking up the wrong tree.

EDIT: I just wrote a description of how the turboii throttles work and at the end I thought *Does he have a turbo or non turbo*, and i looked at your profile and EEEEEEKKKKKKK! I just wasted a bunch of time. I thought you had a turbo.

Anyway, the NO 2 secondary throttle plates (outboard set) are held closed when the engine is cold, by a vacuum from a water thermo valve at the rear of the throttle body. White or cream looking with two nipples on it. It feeds a diaphram on the front of the throttle body which has a lever on it attached to the throttle linkage for the secondary plates. I have NEVER owned or found in a wreck yard a diaphram that worked. Put a vac hose on the inlet to that diaphram and suck. I bet money it won't hold a vacuum. Broke

But what happens with those No2 secondary throttle plates if no vacuum exists is that they are spring loaded open all the time.

Anyway, since the NO 1 secondary throttle plate is still in its closed position at idle it matters not where theNo 2 secondary is. Its on the whole not a player at idle if its wide open.

So, on to your problem. The up/down cycling. It's probably tps related since your engine idles around 800 at idle. The tps setting is not a big deal. Fully heat the car up and leave it idling. Get your DIGITAL multimeter out, cheap one works just fine. Put your positive lead of the meter up the backside of the green wire with a red stripe (located at the tps electrical connector). Leave the plug connected. Now put your negative meter lead on a good ground, like the battery ground or just the intake manifold. Put the meter on volts DC. With a fully warmed up engine the reading should be approx 1 (one) volt. If you need to adjust the tps screw which ever way gets you to one volt. Done. IF you see 0.95 or 1.05 its not a big deal. The FSM says APPROX ONE VOLT AT IDLE. APPROX is approx. I have no problems if I delibertly set it to 0.90 or 1.15volts. Not a big deal.

You shocked me. You've been reading the FSM. EEEEEEKKKKKKKK! Scary. Keep up the good work, especially using a piece of electrical wire strands to set the primary throttle plates. Gone...time restraints.

Thanks Hailers. That makes sense...that when the No1 throttle valves are closed ... the No2s have no influenece. Go it.

Again, just for clarity, this problem exists on my 91 Vert n/a.

By the way, the dashpot seems to be functioning properly. When I release the valves, the dashpot slowly closes them. Not the case on my 86 n/a. Slams shut.

I'm off to check the TPS. Will advise what I find.

screw under bracket

Guys, TPS closed position voltage, when engine is hot, is at 0.47 Volts. I'm low (vs the approx 1.0V spec). Did notice that it was at 1.0 Volts when idleing at 1800 rpm. Once the engine warmed up, rpm dropped to 800rpm and then the voltage also dropped to 0.47 volts.

Also noticed that the oscillation comes back when I move the throttle plates via cam to a postion giving me 1.0Volts (at approx 1500rpm).

So, the FSM says to loosen the mounting bolts to adjust the throttle sensors. I don't get it. How is there any adjustment in a set of holes. There's no slots.

Also, it looks like there's more than just the two bolts. Appears to be a 3rd fastener (philips head screw from the bottom) holding the plate to a second horizontal plate. Going to try to get a right angle driver to get that loose...still don't see how I'm going to get any play by doing this.

Am I adjusting the right brackets and bolts? Pics attached.

Thanks again.

Looks like my other reply didn't make it.

I checked the TPS voltage when hot. I measured 0.47volts (800rpm). I'm low. You nailed it Hailers.

Noticed that before the idle dropped to 800, when at approx 1800 rpm, the voltage was at 1.0volts.

I played with the cam to watch the voltage increase and noticed that at 1.0volts, the oscillation came back ..(1200 to 1500rpm) approx.

So, to get me up to 1.0volts, the FSM says to adjust the mouting bolts and move the throttle sensors.

I don't get it. The bolts are through holes...I don't see any slots. How is there enough play to make any adjustment? Also, there appears to be a philip head screw head way under that L bracket holding the bracket in place. Can't get to it.

Going out to get a right angle philips. Is this really going to work? Am I adjusting the right bracket?

Thanks.

bracket pic attached.

Sorry, I don't own nor have I ever messed with a series five tps. But....the 91 FSM says that at idle, pin 2F should read Approx 1 (one)volt (narrow range sensor). It's still a green/red wire though at the tps.

I remember once reading about series five tps setting and how this guy suggested *bending* the bracket. I don't see how a small bending of the bracket could hurt as long as everything lined up when you were finished. Like the plunger to whatever pushes on it.

The jpg you attached only showed part of the throttle by the way, at least on my computer.

Hailers, I read the same thing in my FSM and checked the Green cable exactly as you said, through the backside of the connector. So, everything is the same in that regards. I measured 0.47 Volts vs the spec of 1.0Volts.

- page F2-78 shows a table where
2F: Narrow range should be 1.0V
2G: Full range should be 0.8V

- page F2-81 shows a table where both are
0.75 - 1.25 Volts.

Either way, I was low.

After relooking at the FSM explanation, I realized that I must have overlooked the diagram showing the adjustment screw. Thought that was for something else. It's shown as a mirror image compared to my S5. Maybe they're showing the Turbo version??? I opened that screw up which allowed the scissor mechanism to drive the cam away from the piston. Now I'm sitting at 1.0Volts.

Will let the engine cool and see what happens in a few hours.

Have attached the picture of the screw that I adjusted to get me there.

Hope this works.

Any comments?

Hailers, I read the same thing in my FSM and checked the Green cable exactly as you said, through the backside of the connector. So, everything is the same in that regards. I measured 0.47 Volts vs the spec of 1.0Volts.

- page F2-78 shows a table where
2F: Narrow range should be 1.0V
2G: Full range should be 0.8V

- page F2-81 shows a table where both are
0.75 - 1.25 Volts.

Either way, I was low.

After relooking at the FSM explanation, I realized that I must have overlooked the diagram showing the adjustment screw. Thought that was for something else. It's shown as a mirror image compared to my S5. Maybe they're showing the Turbo version??? I opened that screw up which allowed the scissor mechanism to drive the cam away from the piston. Now I'm sitting at 1.0Volts.

Will let the engine cool and see what happens in a few hours.

Have attached the picture of the screw that I adjusted to get me there.

Hope this works.

Any comments?

Hailers, I read the same thing in my FSM and checked the Green cable exactly as you said, through the backside of the connector. So, everything is the same in that regards. I measured 0.47 Volts vs the spec of 1.0Volts.

- page F2-78 shows a table where
2F: Narrow range should be 1.0V
2G: Full range should be 0.8V

- page F2-81 shows a table where both are
0.75 - 1.25 Volts.

Either way, I was low.

After relooking at the FSM explanation, I realized that I must have overlooked the diagram showing the adjustment screw. Thought that was for something else. It's shown as a mirror image compared to my S5. Maybe they're showing the Turbo version??? I opened that screw up which allowed the scissor mechanism to drive the cam away from the piston. Now I'm sitting at 1.0Volts.

Will let the engine cool and see what happens in a few hours.

Have attached the picture of the screw that I adjusted to get me there.

Hope this works.

Any comments?

struggling with the connection....looks like multiple replys were submitted.

Here's another shot at sending the linkage mechanism that I adjusted.

Well darn. I replied a half hour ago but must have hit the wrong button.

After the car cools down the reading on the tps WILL increase, and I think you know that. On my car after it sits and gets stone cold, it'll read about 1.65v in the morning....til it warms up and then after the thermowax finishes its job I'm back to one volt again. Normal operation.

Oh. Just saw your last jpg. Thats the tps adjustment screw. Used only for setting the tps. NOT for anything else such as increasing/decreasing the rpms etc.

The screws for setting the thermowax/fast idle screw are on the aft, bottom of the throttle body.
I never worked on a series five, but that body looks close enough for me to say the above.

The diaphram I talked about in a earlier post is that mushroom device in the left of the last jpg you sent. Off to other things now.

Just tried restarting after several hours of cooling down the engine.

NO more oscillation. Nice slow reduction in rpm from 1800 down to 800. Can I say that we fixed it without jinxing myself?

Going to verify again tomorrow morning.

I'm quietly jumping up and down.

Thanks for sticking with me on this everyone!:D

Verified again this morning.

TPS sensor voltage readings : Green wire to ground.
1.8 Volts at cold
1.0 Volts at hot

FIXED !!!!!

Thanks again everyone.